> For the complete documentation index, see [llms.txt](https://docs.paragontruss.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.paragontruss.com/design/how-to/general/reference-lines.md).
# Create and Modify Reference Lines
Before you begin, select a profile truss, such as a `Common` truss.
## Add a Reference Line
### Step 1 - Click `Create` and choose `Reference Line`
You can also right-click in empty space, or press `Ctrl + Q`, and choose `Reference Line`. The `Reference Line Insertion` panel opens in the right sidebar.
{% hint style="success" %}
Tip
You can use the keyboard shortcut `Ctrl + Q + R` to begin inserting a reference line.
{% endhint %}
### Step 2 - Click where the line starts, then where it ends, which fills in `First Selection` and `Second Selection`
What you click decides the kind of line: see [Creating Specific Line Types](#creating-specific-line-types) below.
## Add Multiple Reference Lines
Only division lines can be added several at a time. They're spaced evenly between two lines.
### Step 1 - Click `Create` and choose `Reference Line`
### Step 2 - Click the line where the run of lines starts
A Quantity box appears at the top right of the scene.
### Step 3 - Type how many lines you want in the Quantity box, or press the + and - keys
Press `+` to add a line to the run and `-` to remove one.
### Step 4 - Click the line where the run of lines ends
## Creating Specific Line Types
### Point-to-Point Line
`Point-to-Point` lines are created by clicking two intersections.
### Point-Slope Line
`Point-Slope` lines are created by clicking an intersection and clicking again to set the angle.
### Parallel Line
`Parallel` lines are created by clicking a line and clicking again at the desired offset.
### Perpendicular Line
`Perpendicular` lines are created by clicking a line followed by an intersection.
### Division Line
`Division` lines are created by clicking a line followed by another line.
## Deleting Reference Lines
### Step 1 - Select a reference line, such as `B1` under `Reference Lines`, or click it in the scene
### Step 2 - Click `Delete Selected Item(s)`
You can also press the `Delete` key.
{% hint style="info" %}
Note
A reference line can't be deleted while other lines, members, braces or bearings depend on it: the app tells you which ones. Standard reference lines can't be deleted at all.
{% endhint %}
## Delete Unused Reference Lines
### Step 1 - Click `Menu` next to `Reference Lines` and choose `Delete Unused Reference Lines`
## Modifying Reference Line Properties
### Step 1 - Select a reference line, such as `B1` under `Reference Lines`, or click it in the scene
### Step 2 - Make your changes in the properties, such as `2'` in `Offset`
The properties depend on the line's `Type`: for example, `Offset` for a parallel line, `Base Point` and `End Point` for a point-to-point line, or `Division factor` for a division line.
{% hint style="danger" %}
Warning
Modifying a reference line that other objects and their reference lines depend on can have unintended consequences, especially when changing fundamental properties like the Line Type.
{% endhint %}
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.
Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:
```
GET https://docs.paragontruss.com/design/how-to/general/reference-lines.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
